Facts about Pi

Date: 03/09/97 at 17:37:53
From: Anonymous
Subject: pi

What are a few interesting facts about pi?

Date: 03/11/97 at 10:31:05
From: Doctor Ken
Subject: Re: pi

Hi there,

Pi was known by the Egyptians, who calculated it to be approximately 
(4/3)^4 which equals 3.1604. The earliest known reference to pi occurs 
in a Middle Kingdom papyrus scroll, written around 1650 BC by a scribe 
named Ahmes. He began the scroll with the words: "The Entrance Into 
the Knowledge of All Existing Things" and remarked in passing that he 
composed the scroll "in likeness to writings made of old." Toward the 
end of the scroll, which is composed of various mathematical problems 
and their solutions, the area of a circle is found using a rough sort 
of pi.

Around 200 BC, Archimedes of Syracuse found that pi is somewhere about 
3.14 (in fractions; Greeks did not have decimals).  Pi (which is a 
letter in the Greek alphabet) was discovered by a Greek mathematician 
named Archimedes. Archimedes wrote a book called The Measurement of a 
Circle. In the book he states that Pi is a number between 3 10/71 and 
3 1/7. He figured this out by taking a polygon with 96 sides and 
inscribing a circle inside the polygon. That was Archemedes' concept 
of Pi. 

New knowledge of Pi then bogged down until the 17th century. Pi was 
then called the Ludolphian number, after Ludolph van Ceulen, a German 
mathematician. The first person to use the Greek letter Pi for the 
number was William Jones, an English mathematician, who coined it in 
1706.

In the 1800's people sat down for years on end to find the values of 
pi to about 1000 places. Imagine doing this by hand with no 
calculators. This has become a thing of the past, since the tedium 
that used to be done by hand is now done by computer. 


Facts About Pi

 - Pi is the ratio of the circumference of a circle to the diameter. 

 - 2 Pi in radians form is 360 degrees. Therefore Pi radians is 
   180 degrees and 1/2 Pi radians is 90 degrees. 

 - e raised to the i*pi power equals -1 (e is the base of the natural 
   logarithm and i is the imaginary number which is the sqare root 
   of -1). 

 - Pi day is celebrated on March 14 at the Exploratorium in San 
   Francisco (March 14 is 3/14).

 - All the digits of Pi can never be fully known. 

For more about Pi see the Dr. Math FAQ:

  http://mathforum.org/dr.math/faq/faq.pi.html   

- Doctor Ken, The Math Forum
Check out our web site!  http://mathforum.org/dr.math/